Micromagnetic Study of Spin Transfer driven Vortex Dipole and Vortex Quadrupole Dynamics

TL;DR

This paper presents a micromagnetic analysis of vortex dipole and quadrupole dynamics driven by spin transfer in spin-valve structures, revealing how geometry influences their rotation and translation behaviors.

Contribution

It provides a systematic micromagnetic study of vortex and antivortex dynamics in spin-valves with nano-aperture current injection, highlighting shape-dependent behaviors.

Findings

Vortex dipoles exhibit rotation and translation depending on device geometry.

Vortex quadrupoles show rotation behavior influenced by shape and size.

The behaviors are explained within a micromagnetic framework.

Abstract

Vortices and antivortices are typical non uniform magnetization configurations that can be achieved in spin-torque oscillators with in-plane materials. Dynamics of a vortex-antivortex pair, namely vortex dipole, were predicted and already observed. In this paper, we present a systematic micromagnetic study on that kind of dynamics in different spin-valves where the current is injected through a nano-aperture. Rotation and translation of vortex dipoles and rotation of vortex quadrupoles are shown depending on the shape and the size of the spin-valve. The origin of the different behaviors is explained within a micromagnetic framework.